Nonesuch continues to keep its Steve Reich discography up to date with major works from 2009 and 2010, alongside a smaller earlier piece, Dance Patterns for pairs of xylophones, vibraphones and pianos, from 2002. Reich's string-quartet memorial to the victims of the World Trade Center atrocity, WTC 9/11, was finished last year and introduced on both sides of the Atlantic as part of the concerts to mark the composer's 75th birthday a few months ago. It uses samples of news documentary recordings, as well as interviews with Reich's New York neighbours and eye-witnesses as the starting point for the four movements, with the quartet writing (itself overlaid twice on tape) developed from the recorded sounds and speech patterns. It's short – 15 minutes – but perfectly proportioned. Mallet Quartet, for two vibraphones and two marimbas, was written before the string quartet. It's almost like a glance back to Reich's music of the 1970s, with the dense, uniform soundworld, many of the textures generated from interlocking canons, and much less harmonic movement than in most of his recent pieces. But like everything he writes, it's wonderfully lucid, and calculated precisely.